The present invention refers to a measuring or graduated vessel for receiving liquids to be tested such as blood, blood plasma or the like.
German patent specification DE-PS 29 37 195 discloses a measuring vessel with a circular bottom provided with a projecting central limiter pin and forming a track for a spherical body by which the coagulation behavior of blood can be mechanically determined in a very precise manner. In addition to this analytical process, photometric analysis is used to carry out certain measurements of blood, blood plasma or the like. In order to conduct a proper photometric analysis, it is necessary to enable an unobstructed passage of light emitted from a light source through the wall of the measuring vessel. The cylindrical configuration of the conventional measuring vessel is, however, unsuitable for photometric measurement as the curvature of the wall deflects incident light rays, leading to inaccurate results.
In addition, the conventional measuring vessel conflicts with an automatic analyzing process. Especially in connection with a photometric analysis, the cylindrical configuration of the measuring vessel complicates an exact positioning of the measuring vessel relative to the light source. This, however, is a precondition for an unobjectionable measurement. Apart from complicating the automatic feed and positioning of the measuring vessel, the cylindrical configuration also conflicts with an optimal utilization of the available storage space in a storage box which generally contains a plurality of measuring vessels and is transported in its entirety to a consumer for automatic withdrawal of a measuring vessel. In order to enable accommodation of a greatest possible number of measuring vessels, it necessarily follows that the existing space of the storage box should be utilized in an optimum manner. Evidently, the cylindrical configuration of the measuring vessels is in conflict with such a demand.